$ { {4} \times \left[\begin{array}{rrr}{0} & {2} & {0} \\ {-2} & {1} & {0}\end{array}\right] = {?} } $
Solution: To multiply a matrix by a number, multiply each item of the matrix by the number. ${\left[\begin{array}{rrr}{4}\times{0} & {4}\times{2} & {4}\times{0} \\ {4}\times{-2} & {4}\times{1} & {4}\times{0}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{rrr}{0} & {8} & {0} \\ {-8} & {4} & {0}\end{array}\right]}$